one_fast_300zx

hey all. this has probably been asked before and i have looked but i cant find anything that has my exact problem. my 87 300zx non-turbo 5 speed. when the car is idling it has a skip to it, not real bad almost like its just becuase of holes in my exhaust that i have to fix (damn NY weather) and when im at low speed (mostly under 40 mph) in 4th or 5th it has the skip. but when im doing anything over 40ish she is nice and smooth. i know what mostly causes this problem and have replaced the spark plugs and wires, fuel pump(that was bad anyway),fuel filter,air filter,pcv valve,and did a fuel system cleaner(the one where the cleaning stuff is sprayed in through the brake master cylinder hose). im pretty good with things like this but it seems to have stuck. any and all help is greatly appreciated. thanks and i know you guys will know what my problem is.

AZ-ZBum

I think you pretty much nailed it.

one_fast_300zx

i think thats what it is because the gaskets for the cat. blew out and there a 2 more small holes. but i was mostly was just curious if anyone thought it was anything else, like the cap and rotor or coil. i think im just going to cheaply fix the holes for now or not even worry about it, since i will have the 87 turbo here in about 2 months or so. thanks for the opinion though.